Add runtime support for the upcoming string implementation.

runtime/include/chpl-mem-desc.h:
  Add new memory descriptor types STRING_INIT_DATA and STRING_COPY_REMOTE.

runtime/include/chpl-string.h
runtime/src/chpl-string.c:
  Add new support functions.

  - initString() takes 2 strings, old and new.  If old is longer than
    new, it copies new into old and returns old.  Otherwise, it frees
    old and allocates space for a copy of new.  I'm not crazy about
    this name, so any suggestions are welcome.

  - remoteStringCopy() takes a remote node id, remote address, and
    string length.  It allocates space for the remote string and
    copies the string from the remote locale.

runtime/src/chpl-string-support.c:
  Removed incorrect comments regarding the use of the string literal "".
Merge branch 'master' of github.com:chapel-lang/chapel into record-string
Rename and change functionality of runtime function for allocating a local string.

I never liked the name initString, but I found a better name for it
due to restructuring the functionality.  It's now called stringMove(),
which copies the len bytes of src into dest and returns dest.  If dest
is "", then it allocates a new buffer for the copy, and returns that
buffer.  It is the caller's responsibility to make sure the src is
large enough to hold dest.

This puts the buffer reuse policy into the new string module.  Note
that the allocation must be done in the runtime since there is no way
to call chpl_here_alloc() from the runtime.
Updating comment on stringMove().
New string record.
Initial draft of associative primer
Removing associative content from domains primer
Informing reader to refer to associative primer
Making this example clearer
First stab at a directory-specific walker
Oops, accidentally committed this on master
Merge branch 'master' of github.com:chapel-lang/chapel into assoc-primer
Adding associative primer to makefile
Merge branch 'master' of github.com:chapel-lang/chapel into record-string
Better header about other sources of information for domain types
Many style/wording/organization improvements. More examples of how associative arrays are 'just as good' as other arrays
New string implementation and memory leaks tests.
Changing prettyPrint format to use brackets instead of curly braces. This is done to be more consistent with array-literal syntax
Split the test classes/bradc/arrayInClass/genericArrayInClass-otharrs into a test and a future.

The test shows the ability to create and iterate over arrays-of-arrays that are stored in
classes (which is a valuable test by itself).

The future is due to a bug in zippered iterator inlining, which makes the test fail unless
inlining is turned off.

So, iterator inlining is turned off in the .compopts file associated with the main test.
Details of the bug are provided in the .bad and .future files in the added future test.
Merge branch 'test' of github.com:sungeunchoi/chapel into test